Health-Bac contains the most extensively researched probiotic available: Ecologic 500. Health-Bac contains Bifidobacterium infantis, lactis, longum, Enterococcus faecium, Lactobacillus acidophilus, paracasei, plantarum, salivarius, and Lactocuccus lactis. Health-Bac has been clinically demonstrated to readily implant in humans. Always use Health-Bac when taking large amounts of Oreganol and/or OregaResp P73 daily. Scored among the top two probiotics in the world use Health-Bac; it really does implant and thus is effective.